Ischemic diseases are significant causes of mortality in industrialized nations. It is well established that tissue damage results from ischemia (insufficient blood flow to a tissue) followed by reperfusion (reflow of blood to the tissue). Ischemia and reperfusion cause disturbance of microcirculation with ensuing tissue damage and organ dysfunction. Organs such as the kidney, heart, liver, pancreas, lung, brain and intestine are known to sustain damage following ischemia and reperfusion.
In ischemic conditioning (IC), a tissue or organ or region of a subject's body is deliberately subjected to brief ischemic episodes, followed by brief reperfusion episodes. IC has been found to render the tissue, organ or region resistant to injury during subsequent ischemic episodes. The phenomenon of ischemic conditioning has been demonstrated in most mammalian tissues. IC is now recognized as one of the most potent innate protective mechanisms against ischemia-reperfusion (I-R) injury.
Remote ischemic conditioning (RIC) refers to the deliberate induction of transient ischemia in a subject at a region remote from at least some of the tissue to be protected. Often, RIC includes inducing transient ischemia in a subject's limb to protect organs remote from the limb, such as the myocardium. Myocardial protection has been demonstrated by a variety of remote stimuli, including renal ischemia, liver ischemia, mesenteric artery ischemia, and skeletal muscle hind limb ischemia.
RIC, in the broadest sense, involves deliberate induction of an ischemic period followed by a reperfusion period. The ischemic period may involve complete cessation of blood flow (blood flow occlusion). Such ischemic periods may be induced by applying super-systolic pressures on a region of the body, such as for example a limb. Alternatively, ischemic periods may also be induced by applying a less than systolic pressure.
RIC may be performed prior to (pre-), during (per-) and/or following (post-) an ischemic injury or other injury which benefits from RIC. RIC has shown benefit in reducing or preventing damage resulting from, myocardial infarction and trauma, inter alia.